The present invention is a dental implant system having a unique band of connective tissue rings and grooves. The band may be part of a dental implant or part of a separate abutment that is used in conjunction with a dental implant. The band is designed to minimize tissue loss and to reduce the risk of bacterial infection in the implant site. The band is intended to be positioned on the portion of the implant or the abutment such that when the dental implant system is mounted within a patient's jawbone, the connective tissue band is positioned within the connective tissue layer, or soft tissue, adjacent to the bone.
Dental implants are embedded in the jaw bone and serve to anchor one or more artificial teeth or dentures. Typically, the implant is set in the bone and an abutment is mounted on the implant. Important to the success of such devices is the rigid anchoring of the implant in the bone, and several journal articles and patents have proposed various methods for achieving rigid anchoring (see U.S. Pat. No. 5,344,457 and incorporated herein by reference). For example, U.S. Pat. No. 4,713,003, issued to Symington et al. describes an implant that has a tapered external body, resulting in a better distribution of the stresses acting on the device in situ than is achieved with cylindrical body implants. U.S. Pat. No. 5,344,457, issued to Pilliar et al, describes an implant that has a body with a non-porous surface on the upper portion of the implant and a porous surface on the lower portion of the implant. The porous surface provides interstices into which bone is permitted to grow once the implant is accommodated within the bone.
As reported in U.S. Pat. No. 6,454,469, issued to Hollander et al, and incorporated herein by reference, it is known to provide a variety of surface effects to enhance osseo-stability of the implant within bone. In the '469 patent a device is taught that has a collar portion consisting of proximal and distal cylindrical sub-segments, one having a surface effect adapted for the promotion of growth of soft tissue and the other adapted for the promotion of bone or hard tissue growth. Specifically, the '469 patent teaches a dental implant having a distal segment with a surface that defines an ordered microgeometric repetitive surface pattern in the form of a multiplicity of alternating ridges and grooves, each having a fixed or established width in a range of about 2.0 to about 25 microns and a fixed or established depth in the range of about 2.0 to about 25 microns. While the device of the '469 patent recognizes that bone and soft tissue react differently with implant surfaces, it fails to recognize that academic studies have demonstrated that pore sizes of 10 microns or less lead to little or no fibrous ingrowth, and that a pore size of greater than about 30 microns is needed to give sufficient blood supply for adequate blood vessel ingrowth. This ingrowth is believed to be a factor in impeding epithelial migration toward the boney region of the implant site, and the less epithelial migration into the site, the lower the probability of infection development.
As is known in the art, the abutment of the dental implant generally has a first portion that abuts the implant and that is preferably positioned so as to lie within the connective tissue layer, a second portion that abuts the first portion and is preferably positioned so as to lie within the attached epithelial layer, and a third portion that abuts the second portion and is preferably positioned so as to lie within the sulcular epithelial layer. Each of the tissue layers are generally believed to be about 1 mm in depth.
Because of its proximity to the bone, it is imperative that the connective tissue forms a tight bond with the first portion of the abutment. If gaps remain between the connective tissue and the abutment, bacteria may penetrate into the gap and into the boney region, causing infection. The prior art has recognized the need for the connective tissue segment of the abutment to have a surface designed to encourage tissue attachment to the abutment. For example, U.S. Pat. No. 6,527,554, issued to Hurson, et al., teaches a dental implant system that has a soft tissue attachment zone. To promote attachment of connective soft tissues, the soft tissue attachment zone is preferably roughened, and is at least about twice as rough as the smooth machined and/or polished surfaces of prior art abutments in the transgingival region. U.S. Pat. No. 6,419,491, issued to Ricci, et al., teaches a dental implant with a platform section that has a first ordered microgeometric repetitive surface pattern at a distal section and a second ordered geometric pattern at a proximal portion. The second ordered geometric pattern, which exhibits a width of about 2 to about 25 microns and a depth in a range of about 2 to about 25 microns, is deemed to be more suitable for purpose of tissue (as opposed to bone) adhesion or interface. U.S. Pat. No. 6,981,873, issued to Choi, et al., teaches a dental implant with a settling portion formed between an abutment portion and a fixture portion, wherein the average surface textures of the settling portion is between about 1.0 μm to about 2.0 μm.
Although progress has been made with respect to addressing the adhesion of connective tissue to dental implants, the implants of the prior art still fail to promote the degree of adhesion needed to reduce the risk of bacterial infection.